Raphael E. Liesegang
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Raphael E. Liesegang
Raphael Eduard Liesegang () (1 November 1869 – 13 November 1947) was a German chemist, photographer and entrepreneur born in Elberfeld. He is known for his work on Liesegang rings. He also helped develop the methods of capillary analysis, a precursor to paper chromatography, published a paper on the possibility of television (years before the discovery of the electron), contributed to chromosome theory, worked on properties of aerosols and gelatins, the origins of silicosis, the role of carbon dioxide in plant life and the mechanism of both black and white and colour photographic processes. The son of a painter (and eventual photographer), Liesegang longed for an artistic career but lacked the ability to draw or paint. His father would later invent a camera and photography would go on to be one of Liesegangs passions. Research into photographic emulsions led to his personal discovery of Liesegang rings. He was not the first person to observe the effect, but they bear his name, ...
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Elberfeld
Elberfeld is a municipal subdivision of the German city of Wuppertal; it was an independent town until 1929. History The first official mentioning of the geographic area on the banks of today's Wupper River as "''elverfelde''" was in a document of 1161. Etymologically, ''elver'' is derived from the old Low German word for "river." (See etymology of the name of the German Elbe River; cf. North Germanic ''älv''.) Therefore, the original meaning of "elverfelde" can be understood as "field on the river." Elverfelde received its town charter in 1610. In 1726, Elias Eller and a pastor, Daniel Schleyermacher, founded a Philadelphian society. They later moved to Ronsdorf in the Duchy of Berg, becoming the Zionites, a fringe sect. In 1826 Friedrich Harkort, a famous German industrialist and politician, had a type of suspension railway built as a trial and ran it on the grounds of what is today the tax office at Elberfeld. In fact the railway, the Schwebebahn Wuppertal, was eventu ...
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Black And White Photography
Monochrome photography is photography where each position on an image can record and show a different ''amount'' of light, but not a different hue. It includes all forms of black-and-white photography, which produce images containing shades of neutral grey ranging from black to white. Other hues besides grey, such as sepia, cyan, blue, or brown can also be used in monochrome photography. In the contemporary world, monochrome photography is mostly used for artistic purposes and certain technical imaging applications, rather than for visually accurate reproduction of scenes. Description Although methods for photographing in color emerged slowly starting in the 1850s, monochrome imagery dominated photography until the mid–twentieth century. From the start, photographic recording processes such as the daguerreotype, the paper negative and the glass collodion negative did not render the color of light (although they were sensitive to some colors more than others). The result w ...
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People From Elberfeld
A person ( : people) is a being that has certain capacities or attributes such as reason, morality, consciousness or self-consciousness, and being a part of a culturally established form of social relations such as kinship, ownership of property, or legal responsibility. The defining features of personhood and, consequently, what makes a person count as a person, differ widely among cultures and contexts. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as they were or will be at another time despite any intervening changes. The plural form "people" is often used to refer to an entire nation or ethnic group (as in "a people"), and this was the original meaning of the word; it subsequently acquired its use as a plural form of per ...
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1947 Deaths
It was the first year of the Cold War, which would last until 1991, ending with the dissolution of the Soviet Union. Events January * January–February – Winter of 1946–47 in the United Kingdom: The worst snowfall in the country in the 20th century causes extensive disruption of travel. Given the low ratio of private vehicle ownership at the time, it is mainly remembered in terms of its effects on the railway network. * January 1 - The Canadian Citizenship Act comes into effect. * January 4 – First issue of weekly magazine ''Der Spiegel'' published in Hanover, Germany, edited by Rudolf Augstein. * January 10 – The United Nations adopts a resolution to take control of the free city of Trieste. * January 15 – Elizabeth Short, an aspiring actress nicknamed the "Black Dahlia", is found brutally murdered in a vacant lot in Los Angeles; the mysterious case is never solved. * January 16 – Vincent Auriol is inaugurated as president of France. * January 19 – Ferry ...
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1869 Births
Events January–March * January 3 – Abdur Rahman Khan is defeated at Tinah Khan, and exiled from Afghanistan. * January 5 – Scotland's oldest professional football team, Kilmarnock F.C., is founded. * January 20 – Elizabeth Cady Stanton is the first woman to testify before the United States Congress. * January 21 – The P.E.O. Sisterhood, a philanthropic educational organization for women, is founded at Iowa Wesleyan College in Mount Pleasant, Iowa. * January 27 – The Republic of Ezo is proclaimed on the northern Japanese island of Ezo (which will be renamed Hokkaidō on September 20) by remaining adherents to the Tokugawa shogunate. * February 5 – Prospectors in Moliagul, Victoria, Australia, discover the largest alluvial gold nugget ever found, known as the "Welcome Stranger". * February 20 – Ranavalona II, the Merina Queen of Madagascar, is baptized. * February 25 – The Iron and Steel Institute is formed in Lon ...
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19th-century German Chemists
The 19th (nineteenth) century began on 1 January 1801 ( MDCCCI), and ended on 31 December 1900 ( MCM). The 19th century was the ninth century of the 2nd millennium. The 19th century was characterized by vast social upheaval. Slavery was abolished in much of Europe and the Americas. The First Industrial Revolution, though it began in the late 18th century, expanding beyond its British homeland for the first time during this century, particularly remaking the economies and societies of the Low Countries, the Rhineland, Northern Italy, and the Northeastern United States. A few decades later, the Second Industrial Revolution led to ever more massive urbanization and much higher levels of productivity, profit, and prosperity, a pattern that continued into the 20th century. The Gunpowder empires, Islamic gunpowder empires fell into decline and European imperialism brought much of South Asia, Southeast Asia, and almost all of Africa under Colonialism, colonial rule. It was also marked ...
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Photographic Paper
Photographic paper is a paper coated with a light-sensitive chemical formula, like photographic film, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a visible image; with most papers the image density from exposure can be sufficient to not require further development, aside from fixing and clearing, though latent exposure is also usually present. The light-sensitive layer of the paper is called the emulsion. The most common chemistry was based on silver halide (the focus of this page) but other alternatives have also been used. The print image is traditionally produced by interposing a photographic negative between the light source and the paper, either by direct contact with a large negative (forming a contact print) or by projecting the shadow of the negative onto the paper (producing an enlargement). The initial light exposure is carefully controlled to produce a gray scale image on th ...
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Düsseldorf
Düsseldorf ( , , ; often in English sources; Low Franconian and Ripuarian: ''Düsseldörp'' ; archaic nl, Dusseldorp ) is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in the state and the seventh-largest city in Germany, with a population of 617,280. Düsseldorf is located at the confluence of two rivers: the Rhine and the Düssel, a small tributary. The ''-dorf'' suffix means "village" in German (English cognate: ''thorp''); its use is unusual for a settlement as large as Düsseldorf. Most of the city lies on the right bank of the Rhine. Düsseldorf lies in the centre of both the Rhine-Ruhr and the Rhineland Metropolitan Region. It neighbours the Cologne Bonn Region to the south and the Ruhr to the north. It is the largest city in the German Low Franconian dialect area (closely related to Dutch). Mercer's 2012 Quality of Living survey ranked Düsseldorf the sixth most livable city in the world. Düsse ...
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Photographic Emulsion
Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of glass, films (of cellulose nitrate, cellulose acetate or polyester), paper, or fabric. Photographic emulsion is not a true emulsion, but a suspension of solid particles (silver halide) in a fluid (gelatin in solution). However, the word ''emulsion'' is customarily used in a photographic context. Gelatin or gum arabic layers sensitized with dichromate used in the dichromated colloid processes carbon and gum bichromate are sometimes called ''emulsions''. Some processes do not have emulsions, such as platinum, cyanotype, salted paper, or kallitype. Components Photographic emulsion is a fine suspension of insoluble light-sensitive crystals in a colloid sol, usually consisting of gelatin. The light-sensitive component is one or a mixture o ...
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Colour Photographic Processing
Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.Karlheinz Keller et al. "Photography" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. All processes based upon the gelatin silver process are similar, regardless of the film or paper's manufacturer. Exceptional variations include instant films such as those made by Polaroid and thermally developed films. Kodachrome required Kodak's proprietary K-14 process. Kodachrome film production ceased in 2009, and K-14 processing is no longer available as of December 30, 2010. Ilfochrome materials use the dye destruction process. Deliberately using the wrong process for a film is known as cross processing. Common processes All photographic ...
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